1. Field of the Invention
The invention relates generally to a method of making skin care products and to methods of using such products. This invention also relates to skin care products which moisturize the skin and prevent excessive drying of the skin.
This invention further relates to skin care products which are antimicrobial and help prevent infection by pathogenic microorganisms, and which mitigate against the spread of such pathogens.
In particular, the invention is concerned with formulations for cleansing and moisturizing skin which are antimicrobial, alcohol-free, contain no animal- or petroleum-based products, have a water base, and comprise an absorption enhancer to promote rapid uptake of the formulation by the skin.
This invention still further relates to skin cleansing products which are antimicrobial, and non-irritating and non-drying to the skin after frequent use. The instant invention further relates to skin moisturizing products which are non-greasy, which rapidly penetrate the outer layers of the skin, and which form a shield to prevent loss of moisture from the skin and to shield from exposure of chemicals and detergents commonly found in health/industry works.
2. Background of the Related Art
Excessive drying of the skin is a common problem which is often the result of exposure to wind, sun and low humidity, or a combination of these factors. Frequent washing of the hands can also result in excessive drying. This is particularly true if abrasive soaps, alcohol-based products and other harsh chemicals are used for cleansing.
Skin that has been excessively dried is not only unsightly, but also tends to slough off excessively and to crack, leading to abrasions of the skin surface. Because the skin serves a key role as a physical barrier to the entry of parasites and pathogens, excessive drying can lead to a breach of the barrier and infection by pathogenic bacteria and fungi. Thus cracks or openings in the skin serve as a portal of entry for pathogens and potential pathogens. Even organisms that are normally considered to be non-pathogens can result in opportunistic infection in immunologically compromised individuals. Infections may be mild or severe and may be localized to the initial site(s) of infection or may be systemic and spread throughout the body. Such spread may occur by direct extension to contiguous tissues, or by way of the lymphatics and ultimately by way of the bloodstream.
Thus, the frequent application of many prior art skin cleansing compositions contributes to skin damage, and therefore may indirectly increase the risk of skin infections. Many prior art skin moisturizers contain petroleum products which dissolve latex gloves as worn by workers in diverse fields, including the health care field
Similarly, many prior art moisturizers contain animal-derived products, such as lanolin. It is known that certain animal-derived products may cause skin allergies and/or dermatitis.
Skin care products of the instant invention allow for frequent use of the products to protect the skin and prevent damage due to drying. In so doing, skin care products under the invention help to prevent infection of the skin itself and entry of pathogens through the skin where they may infect underlying tissues.
Skin cleansing products of the instant invention are formulated not only to accommodate continued frequent use without causing drying and cracking of the skin but also, by the inclusion of one or more antimicrobial agents, to prevent the transmission and spread of pathogenic or potentially pathogenic microorganisms.
Skin care products of the instant invention are formulated to promote the absorption of the composition by the skin. In particular, skin care products of the instant invention comprise an absorption enhancing material. The absorption enhancing material of choice under the invention is a form of ceramic hydroxyapatite. Ceramic hydroxyapatite under the invention is in the form of macroporous spheres of predetermined size range, and is chemically pure. It is formed by the agglomeration of crystals of hydroxyapatite, of 0.5 to 1.0 micrometer size range, into spherical particles which are then sintered at high temperature to provide mechanically stable spheres. Ceramic hydroxyapatite which is useful in the practice of the instant invention is exemplified by that manufactured by the Asahi Optical Company, Tokyo. Ceramic hydroxyapatite has been widely used as a chromatographic separation medium (see, for example, R. Kasai et al. J. Chromatography 407, 205 (1987); S. Tsuru et al. J. Immunol. Methods 106, 169 (1988); T. Kadoya et al. J. Liquid Chromatography 9,3543 (1986); T. Kadoya et al. J. Liquid Chromatography 11,2951 (1986).
Apart from ceramic hydroxyapatite referred to above, hydroxyapatite has been produced in several other forms, each with a characteristic particle morphology, size distribution and surface structure, as observed by scanning electron microscopy (T. Kadoya et al. J. Liquid Chromatography 9,3543 (1986).
Hydroxyapatite has also been ascribed various non-chromatographic applications. For example, JP 254415 discloses cosmetic materials containing spherical hydroxyapatite. JP 266066 teaches a melanin-lightening composition including ethyl alcohol and sodium hydroxide. JP 007409 teaches the use of hydroxyapatite for the selective removal of protein from the body surface. JP 179074 discloses the use of hydroxyapatite as an abrasive, to assist in the cleaning of inanimate surfaces. JP 238429 discloses a blending agent, comprising polystyrene beads coated with hydroxyapatite.